Prudence in the Tribunal

Prudence has a serpent wound around her arm and holds a mirror. The reason for the mirror is that a reflection cannot lie, so Prudence can see her true face. The serpent is an allusion to the Gospel of Matthew, in which Christ tells his followers to be as wise as serpents.

Additional information:
Prudence is one of the four cardinal virtues, along with Justice, Fortitude and Temperance.